Electromagnetic device



Dec. 9, 1958 A. RUHLAND ETA].

ELECTROMAGNETIC DEVICE Filed Sept. 12. 1955 Fig.1

Fig.2

United States Patent 2,864,038 ELECTROMAGNETIC DEVICE Alois Ruhland and Josef Fischer, Munich, Germany, assignors to Siemens & Halske Aktiengesellschaft, Munich and Berlin, Germany, a corporation of Germany Application September 12, 1955, Serial No. 533,866- Claims priority, application Germany September15, 1 954 6 Claims. (Cl. 317-171) This invention relates to an electromagnetic device and is particularly concerned with a device for adjustably mounting an armature relative to pole shoes of a stator.

In electromagnetic moving-armature systems for relays, electric switches, bells or buzzers and the like, the working air gaps must be very accurately adjusted by hand after assembly and in the overhauling of the systems. In high-grade relays, the air gaps only amount to fractions of a millimetre. In magnetic systems having, for example, two or more air gaps the air gaps which are set during assembly are likely to be unequal owing to the tolerances which must be allowed in the manufacture of the individual parts.

According to the present invention there is provided an electromagnetic moving-armature device, wherein an armature is arranged to co-operate with a stator, said armature being mounted by adjusting means on a carrier which is arranged to be rotatable about an axis, said axis thus constituting the axis of rotation of the armature, and said adjusting means being such that the operation thereof effects the adjustment of the air gap(s) between the pole piece(s) of the armature, and that (those) of the stator.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made to the accompanying drawing in which:

Figs. 1 and 1a show a part-sectional side elevation and an end elevation respectively of a polarised relay,

Fig. 1b is a part-sectional plan view taken along the line 1b-1b of Fig. 1,

Fig. 2 illustrates a front elevation of a further polarised relay; and

Fig. 2a is a part-sectional plan view taken along the line 2a2a of Fig. 2.

Referring now to the drawings, in Figs. 1a and lb, a winding 1 on a stator is arranged to be energised by current impulses flowing in one direction or the other. Pole shoes 1:: of the stator are of plate form and each of them extends between two corresponding armature pole pieces. The latter are formed by two plates 2 and 3 between which is firmly secured a permanent magnet 4. The parts 2, 3 and 4 of the armature are mounted on a non-magnetic U-shaped supporting stirrup 5 with the aid of two set screws 7 which pass through the stirrup 5 and engage with corresponding threads in the armature plate 2.

The armature is mounted so as to be rotatable by means of pins 5a and 5b which pass through the arms of the stirrup 5 and also through plates 60 and 6b, so that the axis of the pins constitutes the axis of rotation of the armature. The plates 6a and 6b may be made fast with the stator for example, they may be secured to the magnet yokes thereof; the corresponding connection has been omitted for the sake of clarity.

The magnet 4 is so disposed that the magnetic flux it produces is directed perpendicular to the plane which contains the pole shoes In, that is along the lines indicated armature plate 2. The flux distribution in the air gaps due to this magnet is therefore constant, but superimposedon the flux inthe air gaps there are impulses of the exciting flux produced by the impulses in the winding 1. The armature is, therefore, caused to rotate in one direction or theother, according to the nature of the impulses, about its axis of. rotation.

v A corrugated leaf spring 8 is disposed between the stirrup 5 and the armature plate 2 and the distance between the members 8 and 2 may be adjusted to a desired value by corresponding setting of the set screws 7. It is in this manner, by uniform adjustment of both set screws possible to align the part 2 in parallel to the transverse wall of part 5, thereby making the two air gaps or pairs of air gaps symmetrical. In order to align the pole pieces of the armature parallel with the pole shoes of the stator it may be necessary to rotate the armature by a small amount about an axis which is perpendicular to the plane of Figure 1b of the drawing. This may be effected by tightening one or other of the set screws 7.

In Figs. 2 and 2a, the magnetic parts of the armature, that is the permanent magnet 4, and the two plates 2 and 3, are loosely disposed one upon another and are surrounded by a frame comprising a U-shaped stirrup 5 and a leaf spring clip 9. The stirrup is provided with pins 5a and 5b forming the axis of rotation of the armature as described with reference to Fig. l. The ends of the clip 9 extend over the ends of the arms of the stirrup 5 and engage in corresponding apertures in the stirrup, while the active curved portion of the clip 9 presses against the plate 3, to hold the armature fast to the stirrup. The air gaps between the stator and armature pole pieces are again adjusted by means of the set screws 7. In this case, however, the set screws 7 are merely screwed into the stirrup 5 and their tips press against the armature plate 2 against the thrust of the spring clip 9. Thus the clip 9, like the spring 8 described before serves to reduce the possibility of looseness of, or mechanical play between, the parts.

It will be appreciated that in the devices described above re-adjustment of the air gaps is possible at any time by suitable manipulation of the set screws 7.

Changes may be made within the scope and spirit of the appended claims.

What we claim is:

1. A polarized magnetic system comprising a stator having two pole shoes extending therefrom, an armature comprising a permanent magnet carrying two platelike members each forming two pole pieces one for magnetic cooperation with each of said stator pole shoes, and a device for rotatably mounting said armature, said device comprising a cross-sectionally U-shaped carrier made of non-magnetic material, adjusting means for adjustably connecting one of said platelike members with the base of said carrier, means for rotatably mounting the arms of said carrier, and spring means tending to hold said armature away from said carrier.

2. A polarized magnetic system comprising a stator having two pole shoes extending therefrom, an armature comprising a permanent magnet carrying two platelike members each forming two pole pieces one for magnetic cooperation with each of said stator pole shoes, and a device for rotatably mounting said armature, said device comprising a cross-sectionally U-shaped carried made ofv non-magnetic material, adjusting means for adjustably connecting one of said platelike members with the base of said carrier, means for rotatably mounting the arms of said carrier, and spring means tending to move said carrier towards said armature.

3. A polarized magnetic system and cooperation of parts according to claim 2, wherein the ends of said permanent magnet are disposed along planes extending in parallel with the plane. containingthe axis of rotation of said carrier arms, said adjusting means being adapted to displace said armature in a direction perpendicular to said planes and angularly in parallel with said planes but perpendicular to said axis of rotation.

4. A polarized magnetic system and cooperation of parts according to claim 3, comprising screws constituting said adjusting means.

5. A polarized magnetic system and cooperation of parts according to claim 3, comprising screws constituting said adjusting means, and spring means disposed between said base of said carrier and said platelike member of said armature.

6. A polarized magnetic system and cooperation of parts according to claim 3, comprising screws constituting said adjusting means, and spring means connected with the arms of said carrier.

References Cited in the file of this patent UNITED STATES PATENTS 2,219,157 Zenner Oct. 22, 1940 FOREIGN PATENTS 1,080,986 France June '2, 1954 1,097,324 France Feb. 16, 1955 923,563 Germany Feb. 17, 1955 1,103,207 France May 18, 1955 

